Will it be a problem if I have a visitor visa to Sweden from India but now I will be going to Sweden from US instead of India? I will go back to India after Sweden and all the dates in Sweden are same. I am an Indian. I already have US visitor visa.
There's no such thing as a "from" country on a Schengen visa, as far as validity for a specific arrival route is concerned. The place of issue is marked, but this is just where the visa is issued - it doesn't have to be where you start the trip for which the visa is used. The border agent will most likely neither know nor care that you're arriving from a different country than where you received your visa, but even if they do ask about it it won't cause any problems - just give them an honest answer, that you visited the US immediately before visiting Sweden. As long as you have a valid visa, you can arrive from wherever you want.